1. Field of the Invention
The present invention is related to sports shoes, and especially to boots used in the practice of alpine skiing. The invention is especially related to a ski boot, whose structure comprises an upper journalled on the shell base, which must ensure both easy putting on and removal of the boot, as well as provide good retention of the lower part of the leg when forces are produced during front support and rear support while skiing.
2. Description of Background and Relevant Information
Different solutions attempting to resolve the above-cited problem have been analyzed and implemented in various boots that have been commercialized. Thus, the ski boot models known as "Castor" manufactured under the trademark "LE TRAPPEUR", or other boots such as "Concord-Taiga" marketed under the trademark "DACHSTEIN" comprised a shell base whose lateral walls, extending upwardly, were adapted to cooperate with an upper-collar journalled with respect to the shell base and to surround the lower part of the leg of the skier. To generate energy during front support of the skier and to provide good rear support, this upper-collar was latched on the lateral wings of the shell base, provided with two tenons that snapped together in two holes arranged in the upper-collar. The result of this constructional arrangement was that the upper-collar formed, together with the shell base, a more or less homogenous assembly, capable of absorbing stresses resulting from skiing. However, the nature of the different materials used for the different parts of the boot led to a certain "fatigue" of these materials, modifying both the geometry of the parts as well as their mechanical characteristics. On the other hand, such boots, because of the fact that they formed a homogenous assembly, and at the time a guarantee of relative longevity, were not provided with adjustment means enabling the characteristics of the boot, such as the initial angle of advance of the upper, the stiffness of the rear and/or front supports, etc., to be modified.
According to another more recent type of boots, the present Applicant discloses, in French Patent No. 2,643,795, a rear entry ski boot comprising a shell base on which an upper is journalled about a pivot axis of the upper with respect to the shell base. The upper extends rearwardly by two lateral extensions on which the rear spoiler constituting a portion of this upper is journalled. The boot thus comprises non-extensible means, such as a cable, that is anchored laterally on the ends of the pivot axes located on the shell. These non-extensible means then connect two attachment points located on the rear spoiler of the upper at various heights in such a way that the path of the non-extensible means forms a triangular system of non-deformable links whose pivot axis forms one of the peaks. As such, it is clear that this structure generates a resistance force to rear supports whose intensity is applied mainly towards the base of the boot, whereas it should to be perpendicular to the wall of the rear spoiler.